Russia has begun operating Beriev A-50 ’Mainstay’ airborne early warning and control (AEW&C) aircraft over Syria in support of the air group it has deployed to the country. The A-50s, which are modified Ilyushin Il-76 transports with large rotating radar above their rear fuselages, began operating over Syria in late December, a senior UK military source told IHS Jane’s . On 27 December, an aircraft flying in a profile consistent with an Airborne Warning and Control System (AWACS)-type asset was also spotted on the Flightradar24.com website, which collates transponder data in real time. The track, which was not allocated a callsign by the open-source service, showed an aircraft flying back and forth across northwest Syria at in excess of 20,000 ft for more than four hours.